[U-Boot] [PATCH] arm: fix hvc call

[Alexander Graf]

On 18.02.19 14:10, Ibai Erkiaga wrote:
> HVC call makes use of 6 arguments rather than 7 in the same way as SMC
> calls. The 7th argument is optional for both HVC and SMC but is
> implemented as 16-bit parameter and register R7 or W7.

The patch description is lacking a bit more context. Why not change SMC
to also include x7?

> 
> Signed-off-by: Ibai Erkiaga <ibai.erkiaga-elorza at xilinx.com>
> ---
> The issue does not report any error in a normal build as hvc_call is not
> used at all and is optimized by the compiler. Using -O0 triggers the
> error so the patch is intended to fix issues on a ongoing effor to build
> U-Boot with -O0.

This should definitely not go below the --- line as it's critical
information for anyone who later on reads the commit message in the log.


Alex

> 
>  arch/arm/cpu/armv8/fwcall.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/arch/arm/cpu/armv8/fwcall.c b/arch/arm/cpu/armv8/fwcall.c
> index 9957c29..b0aca1b 100644
> --- a/arch/arm/cpu/armv8/fwcall.c
> +++ b/arch/arm/cpu/armv8/fwcall.c
> @@ -28,7 +28,6 @@ static void hvc_call(struct pt_regs *args)
>                 "ldr x4, %4\n"
>                 "ldr x5, %5\n"
>                 "ldr x6, %6\n"
> -               "ldr x7, %7\n"
>                 "hvc    #0\n"
>                 "str x0, %0\n"
>                 "str x1, %1\n"
> @@ -37,7 +36,7 @@ static void hvc_call(struct pt_regs *args)
>                 : "+m" (args->regs[0]), "+m" (args->regs[1]),
>                   "+m" (args->regs[2]), "+m" (args->regs[3])
>                 : "m" (args->regs[4]), "m" (args->regs[5]),
> -                 "m" (args->regs[6]), "m" (args->regs[7])
> +                 "m" (args->regs[6])
>                 : "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7",
>                   "x8", "x9", "x10", "x11", "x12", "x13", "x14", "x15",
>                   "x16", "x17");
> --
> 1.8.3.1
> 
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